Increase, enhance (7)
I believe the answer is:
augment
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">increase</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that augment is a more specific form of increase)</span><br/ ><br/ >'<span class="explanation-format__original">enhance</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ ></span>
(Other definitions for augment that I've seen before include "Enlarge or increase" , "Add to, increase" , "Make greater in size, number, etc." , "Make larger" , "Grow - intensify" .)